Question

What is Peptidoglycan made of?

Answer 1

The peptidoglycan also known as murein sacculus is an important and unique structural element in the cell wall of bacteria. Peptidoglycan is a cell wall component of bacteria which are made of glycan strands which are cross-linked by short peptides, the sacculus is a bag-like structure surrounding the cytoplasmic membrane.

Complete answer:
Peptidoglycan are basically formed by $$\beta$$$(1 - 4)$linked Muramic acid and N-acetylglucosamine residues. Peptidoglycan are composed of many bacteria, bacteriophages and eukaryotes. peptidoglycan contain sugars and amino acids that form a mesh like layer of most microorganisms. As we knew, that peptidoglycan formed from NAM and NAG, the NAM acid is typically a peptide bond consisting of$3 - 5$ amino acids.
Functions of peptidoglycan- they provide structural support in a bacterial cell wall, also in the osmotic pressure of the cytoplasm. Also, peptidoglycan is involved in binary fission which occurs during bacterial cell reproduction.
As we know, bacteria come in different shapes and sizes also, their shape varies according to variant climatic and habitat conditions and the amount of nutrition they get. On the basis of the stain test, gram negative and gram-positive bacteria have been classified. So, the peptidoglycan layer is usually thicker in gram-positive bacteria as a result the positive bacteria absorbs the gentian violet color or stain unlike the gram-negative bacteria which retain color as soon as the decolorizer is being spread.

Note:
The gram-positive bacteria have peptidoglycan layer $20 - 80$ nanometers and gram-negative bacteria have $7 - 8$ nanometers. Depending on Ph and growth conditions, the layer forms $40 - 90\%$ of the cell’s weight in positive bacteria whereas in negative bacteria only $10\%$ around. Thus, the presence of peptidoglycan is a remarkable difference between positive and negative bacteria.